Fiber‐optic Singlet Oxygen [¹O₂ (¹Δ_g)] Generator Device Serving as a Point Selective Sterilizer

Abstract

Traditionally, Type II heterogeneous photo-oxidations produce singlet oxygen via external irradiation of a sensitizer and external supply of ground-state oxygen. A potential improvement is reported here. A hollow-core fiber-optic device was developed with an “internal” supply of light and flowing oxygen, and a porous photosensitizer-end capped configuration. Singlet oxygen was delivered through the fiber tip. The singlet oxygen steady-state concentration in the immediate vicinity of the probe tip was ca 20 fM by N-benzoyl-DL-methionine trapping. The device is portable and the singlet oxygen-generating tip is maneuverable, which opened the door to simple disinfectant studies. Complete Escherichia coli inactivation was observed in 2 h when the singlet oxygen sensitizing probe tip was immersed in 0.1 mL aqueous samples of 0.1–4.4 × 107 cells. Photobleaching of the probe tip occurred after ca 12 h of use, requiring baking and sensitizer reloading steps for reuse.

Synthesis and Characterization of Ru(II) Complexes with π‐Expansive Imidazophen Ligands for the Photokilling of Human Melanoma Cells

“…The ligands 2‐phenyl‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (bip), 2‐(naphthalen‐1‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (1‐nip), 2‐(naphthalen‐2‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (2‐nip), 2‐(9 H ‐fluoren‐2‐yl)‐1 H ‐imidazo [4,5‐ f ][1,10] phenanthroline (fip), 2‐(pyren‐1‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (ippy) and 2‐(anthracene‐10‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (aip) were synthesized according to literature procedures . Compounds [Ru(4,4′‐dmb) 2 Cl 2 ] ∙ 2H 2 O , Ru(4,4′‐dmb) 2 (bip)](PF 6 ) 2 1 , Ru(4,4′‐dmb) 2 (ippy)](PF 6 ) 2 7 and 9,10‐anthracene dipropionate dianion 8 were synthesized as reported in the literature. For our in vitro study, Ru(II) complexes 1 ‐ 7 were converted to their corresponding Cl – salts.…”

Bacterial Inactivation by a Singlet Oxygen Bubbler: Identifying Factors Controlling the Toxicity of 1O2 Bubbles

“…E. coli were grown according to a previously described procedure. 13 Described here briefly, E. coli was revived in Luria Broth and stored at −80 °C. Quantities of E. coli used were in the range of 300 to 3000 CFU/mL and 3 to 30 μg/mL.…”

Generating Singlet Oxygen Bubbles: A New Mechanism for Gas–Liquid Oxidations in Water

“…Our previous results established a singlet oxygen sensitization process with silica end-capped hollow-core fiber optic devices, utilizing the released 1 O 2 for Escherichia coli inactivation 10 in a slow sparging system (9 ppm/h O 2 ). Eisenberg et al 13 reported on a Pyrex tube bound-Rose Bengal photosensitizer, surrounded by lamps, rapidly flowing 3 O 2 , 1 O 2 and N 2 (30 L/min) in a gas-solid system.…”